Method of manufacture of cane crushing rolls



March 14, 1939. HEGENBARTH 2,150,278

METHOD OF MANUFACTURE OF CANE CRUSHING ROLLS Filed Jan. 21, 1937 3 Sheets-Sheet l 3nventor Gitomegs. I

F 2 a o y HEGENBARTH age/Mart? I March 1939.

Patented Mar. 14, 1939 UNITED STATES PATENT OFFICE METHOD OF MANUFACTURE OF CANE CRUSHING ROLLS 3 Claims.

The present invention relates to improvements in methods of manufacture of cans crushing rolls, and has for an object to reduce the expense of manufacture of such rolls, to largely eliminate the amount of machining previously required, and in general to simplify the method of manufacturing such rolls. Y

The invention has been developed in conjunction with a pair of crusher rolls of an improved type which presented certain difficulties in the method of manufacture and created high cost thereof. The steps of the improved method are described in conjunction with said specific construction of crusher rolls and the invention relates to the formation of both the upper and the lower rolls.

It has been heretofore known in the art to provide both upper and lower crusher rolls with annular or circumferential inter-meshing ribs and grooves of large pitch and having hookshaped grooves cut thereacross. Surface friction of the rolls alone was depended on to produce the feed, as the auxiliary lateral grooves could not grip cane that entered between the rolls end A great deal of trouble was experienced in practice with this type of grooving, and eventually all cane had to be cut up by revolving knives before entering the crusher; otherwise the cane fed very badly between the crusher rolls. The old Krajewski type roll with zig-zag grooving would grip the cane after a fashion, but the lateral ridges on same prevented drainage of the expressed juice and caused reabsorption resulting in very poor extraction.

With the replacement of soft, low-fibre canes by harder varieties of high-fibre cane, and with the resultant change in the physical properties of such canes, a corresponding modification of cane crushing equipment became necessary. The crusher types heretofore in general use, developed serious defects in operation: in many cases rotating knives had to be provided to disintegrate the cane prior to its entering the crusher. This, however, was a costly solution, considering the additional cost of installation, constant repairs and the heavy power requirements of such knives.

Of the various crusher types those mostly used are with zig-zag grooves or with circumferential V-grooves and lateral hooks or feed grooves. Those with zig-zag grooves, while disintegrating the cane, will cause reabsorption of a large part of the juice extracted. Crushers of the V-groove type cannot produce an even feed with hard, straight canes, from roll surface friction alone, and capacities fluctuate widely; the lateral hook grooves cannot effectively grip cane entering the crusher lengthwise, and excessive vibration results from the slipping of the rolls over the ends of cane stalks. Furthermore, the absence of any lateralcutting edges prevents effective disintegration, so that often stalks, merely flattened out by the crusher, are carried on through the entire mill tandem.

The present invention aims to avoid the above defects with existing apparatus, and objects of the invention are to provide a cane crusher having an even feed by means of a positive grip of the cane, thorough opening up of the cane cells, disintegration of all the cane entering, freeand unobstructed juice drainage from the bottom roll, vibrationless operation and low cost of operation and maintenance.

A further object of the invention is to increase the capacity of the mill by reason of the fact that there is no slippage of the cane between the rolls; the capacity is therefore not only increased but it is even and can be calculated nicely.

With the invention scraper troubles are largely eliminated as there is no scraper needed on the top roll.

The invention contemplates an improved method of constructing the rolls which will enable the rolls to be manufactured with less special machine'work.

Briefly stated, the invention consists in equipping the top roll with projections of 'a certain novel form hereinafter more fully described, such projections lying in'the grooves of the top roil and entering and cooperating with the hook grooves produced in the circumferential ribs of the lower roll whereby these projections and hook grooves combine to positively feed the cane, even though presented endwise, to grip and cut the cane, to exert a pulling action. upon the cane drawing it between the rolls, to exercise a discharging action upon the cane at the discharge side of the rolls, and to produce a shedding action of any particles of the crushed cane that seek to adhere to the surface of the top roll.

With the foregoing and other objects in View,

the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views,

Figure 1 is a top plan view of an improved cane crusher constructed in accordance with the present invention.

- Figure 2 is a front elevation showing both top and bottom rolls.

Figure 3 is a vertical section taken on the line 33 in Figure 2 showing a fragmentary portion of both rolls on an enlarged scale.

Figure 4 is a section taken on the line 4-4 in Figure 3. v

Figure 5 is a front elevation of a casting of the top roll showing the initial step in its manufacture.

Figure 6 is a fragmentary section taken on the line 6-5 in Figure 5 on an enlarged scale.

Figure 7; is a section taken on the line 'll in Figure 6 showing some of the ribs in finished condition and others as initially cast.

Figure 8 is a front elevation of the lower roll as initially cast, and

Figure 9 is a front elevation of the lower roll as finished.

Referring more particularly to the drawings the top roll is designated generally at ill, and the bottom roll at ll. These rolls are mounted on shafts I2 and I3 connected for simultaneous rotation in relatively opposite directions by the gear wheels M and !5.

The lower roll l is formed with a series of circumferential ribs l5 and circumferential or annular grooves ll lying therebetween. The cross-section of the ribs i6 is triangular. The grooves I! are also triangular to receive and mate with the annular or circumferential ribs it of the top roll, it being understood that such top roll is also formed with the annular or circumferential grooves IQ for receiving the circumferential ribs IB of the bottom roll H. The bottom roll II is totally devoid of any obstructions in the circumferential grooves l'l whereby drainage will not be impeded or in any wise interfered with. Both top and bottom rolls may be provided with hook grooves in any number, such hook grooves being made in the ribs and these hook grooves act in the usual manner. These hook grooves are made in the circumferential ribs.

Referring more particularly to Figure 3, the hook groove employed is preferably of a large size composed of a forward or leading wall 20, a rear or trailing wall 2i and a trough 22 at the common base of the two walls 20 and 2!.

The wall 2| has a shoulder or cutting or shredding edge 23. The words leading and trailing are used in reference to the rotation of the bottom roll which is in the direction of the arrow shown in Figure 3. In other words this bottom roll I I, as viewed in Figure 3, is rotating in a clockwise direction. It will be noted that the troughs 22 or low points of the hook grooves are outwardly beyond the base line 24 of the V-shaped annular grooves H.

The top roll 10 rotates in a counter-clockwise direction when viewed in the position illustrated in Figure 3, as shown by the arrow. In the circumferential ribs I8 of the top roll there may be formed hook grooves 25. Between the circumferential ribs I 8, or in other words in the circumferential grooves #9 are pyramidal projections 26 having the long sloping triangular leading faces 21 which approach coinciding with tangents of the outer solid periphery of the top roll it] at the base'points of the annular grooves 19, and abrupt or short triangular trailing faces 28; the latter faces being more nearly radial with respect to the top roll. In fact, these trailing faces 28 which are of considerably less area than the leading faces 21, are at a slight angle to the radius of the top roll, such faces inclining from the outer ridges 28 inwardly toward the center of the top roll but diverging rearwardly with respect to the direct of rotation of the top roll. The triangular sides of the pyramid projections 26 are merged with the inclined walls of adjacent circumferential ribs H3. The geometrical figure on which the projection 26 is constructed consists of a solid bounded by four triangular sides, of which the leading and trailing faces 21 and 28 are parts. This figure merges into a line which V are base line.

These pyramidal projections 26 are produced in any numbers circumferentially in each of the circumferential grooves of the top roll and they may also be produced in any suitable number transversely across the face of the roll, the same being preferably included in diagonal rows. As many of the hook grooves in the lower cylinder will be provided to cooperate with the pyramidal projections in the manner now described.

In Figure 3, A, B, C, D, E represent five positions of the pyramidal projections 26 on the top roll and A represents an adjoining projection in an adjoining groove located between the positions A and B. It will be noted that the. ridges 29 of the projections 26 extend to within a short distance of the outside diameter of the circumferential ribs l8; and that the ridge 29 is quite sharp in order to grip and cut the cane. The long side or face 2! of the pyramid faces in the direction of roll rotation. This produces an action of wedging the cane into the feed opening in front of the rolls as shown in positions A and A, a pulling action seizing the cane as at position B, a cutting action, as at position C, while the projection is meshed into the hook groove of the bottom roll, a discharging and pushing-away action of the crushed cane, as at position D, and a shedding action of any particles of crushed cane adhering to the projections, as indicated at position E, where the long or leading triangular face 21 presents a vertical surface. The short side 28 of the pyramid is close to radial so as to permit a sharp ridge at 29 and to provide clearance against the point 23 of the hook groove of the lower roll; and to achieve complete shedding of any adhering crushed cane particles in and between the projection positions C, D and E.

The cane enters over a cane chute plate 3%] and leaves on the discharge side over a scraper 3|.

It has beennoted heretofore that the bottoms 22 of the hook grooves in bottom roll H are spaced outwardly from the bottoms of the circumferential V-grooves I! to prevent the catching of the scraper toes in the hook grooves.

By observing position C in Figure 3, it will be appreciated that the relative location of the ridges 29 in the hook groove is chosen so that the clearance between the back wall 28 of a projection 26 and the edge or shoulder 23 of the hook groove is made very close whereby a cutting action between the hook groove edge 23 and the projection takes place shortly ahead of the vertical center line through the rolls, and this cutting action continues to the point'past the vertical roll center where the hook groove and the projection move out of mesh. During this phase the cutting action is assisted by the change of position of the hook groove edge 23 and 2! relative to the adjacent surface of the projection; such edge 23 performing a circular clockwise rotation and a downward movement having passed the vertical center line, by reason of which a tearing action is set up in the space a: by the path described by the edge or shoulder 23 opposite the trailing edge 28rof projection 26 with the cane wedged firmly into this space at.

A similar tearing or shredding effect is produced by the ridge 29 of the projection 26 from the time the mesh of the ridge with the hook groove begins, space 2 being kept the minimum allowable for safe clearance. The ridge 29 of the pyramidal projection 26 is located so as to prolong its close proximity to the gradually sloping Wall of the hook groove as much as possible during the time ridge 29 moves from the approximate crusher center in circular, anti-clockwise rotation to the point where it disengages the hook groove. In this manner, a tearing and shredding action is accomplished by points 23 of the hook grooves and by ridges 29 of the pyramidal projections 26, resulting in efficient disintegration of fibrous canes which from mere pressure would only flatten out. The importance of efficient disintegration of cane in the crusher is plainly indicated by higher recovery of sugar juice in the mills.

In Figure 3, the cane stalks are shown as being fed endwise into the bight of the rolls, coming first under the influence of the leading long triangular faces 21 of the pyramidal projections 26 and being by such faces compressed downwardly and fed along to the feed opening of the rolls.

At position C the cane is shown as very much compacted showing the high degree of pull on the cane and the elimination of slippage whereby the feed is even and uniform and the capacity of the mill greatly increased. At the same time that this positive feed is being produced the cane is rapidly disintegrated to a very high degree and juice drainage is free and unimpeded down through the uninterrupted circumferential grooves of the bottom roll. After extraction of the juice the pyramidal projections rapidly move out of the hook grooves and act to quickly discharge and shed the broken cane.

In accordance with the invention the method of manufacture of the rolls is materially improved. With relation to the bottom roll, the former method was to cut the hook grooves in the roll by machine with specialized costly rigs on the planer. For this purpose a rough cylindrical casting had to be turned to size on the lathe, and circumferential grooves cut in center to furnish tool clearance for cutting hook grooves diagonally. After cutting all of the diagonal hook grooves, the roll was returned to the lathe, and the balance of the circumferential grooves were then cut in a second operation. This involved a great amount of handling and machining. In accordance with the improved method a rough cylindrical casting or blank is first made.

This casting is illustrated in Figure 8, the same being designated at H. Such blank casting of the roll is cast with channels 40 running over the entire width of the roll between flanges. These channels are produced by means of cores in the surface of the rough cylinder. Such channels 40 are cored out and shaped to the final shape of the hook grooves 22. Thereafter the roll is removed to a lathe and the circumferential ribs l6 and grooves are cut therein. Two such ribs iii are indicated in dotted lines in Figure 8. The grooves l1 between adjacent ribs are also shown at the left in Figure 8. The grooves I! are cut deeper than the channels 4|] so that nothing remains of the channels 40 in the annular grooves H; but such channels 40 are only retained in the annular ribs l6 as the hook grooves 22. The machining of the roll surfaces is therefore reduced to a single operation, thus eliminating a great amount of labor and expense.

In the manufacture of the top roll, this roll, as shown in Figure 5, is first cast in the form of a cylindrical blank H1 with the circumferential grooving cast into its surface. Also cast upon its surface are the pyramidal projections 26, the same being cast thereon at an angle corresponding with the angle of the hook groove cores on the bottom roll.

The auxiliary hook grooves may be also cast diagonally across the circumferential grooves. This blank I0 is substantially similar to the finished roll except that a finish allowance 32 is left at the outer edges of the circumferential ribs. This finish allowance is shown more particularly in Figure 7. From this finish allowance the roll is trued up and the sharp tooth ridges out. only machine operation required for the roll surface and grooving. The two ribs at the left in Figure 7 show the finish allowance 32 as the roll comes from the foundry. The two ribs at the right in Figure '7 show the truing down and the cutting of the ribs to produce triangular sharp points.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. The herein described method for forming bottom rolls for cane crushing apparatus, which consists in initially casting a rough cylindrical blank from metal, during the casting operation applying cores in the surface of the rough cylinder to form lateral hook grooves in the initial roughly cast cylindrical blank, transferring the blank so formed to a lathe and cutting spaced circumferential grooves in the blank deeper than the cast hook grooves to produce alternate annular grooves and ribs upon the surface of the cylinder with the hook grooves remaining only in the ribs, and with the bottoms of the hook grooves being spaced radially outward from the base lines of said annular grooves.

2. The herein described method of making crusher rolls, which consists in casting a cylindrical blank with circumferential grooves on its surface and projections in the grooves and with a finish allowance on the outer portions of the circumferential ribs produced between the circumferential grooves, and truing the roll with respect to said finish allowance, and finally cutting sharp tooth edges from said finish allowance.

3. The improved method of making crusher rolls, which consists in casting a cylindrical blank with circumferential grooves on its surface and a plurality of individual projections in the grooves, and lateral auxiliary hook grooves and with a finish allowance on the outer portions of the circumferential ribs produced between the circumferential grooves, truing the roll with respect to said finish allowance, and finally cutting sharp tooth edges from said finish allowance.

FRANCIS HEGENBARTH.

This is the 

